I need help does anyone know how to do this answer 4x + 2x = 3x - 15

How many liters of peroxide should be added to 12 liters of an 8% peroxide solution so that the resulting solution contains 16% peroxide?   original added new amount of peroxide 0.96 liters x 0.96 + x amount of solution 12 liters x 12 + x 0.18 liter 1.14 liters 1.92 liters 2.10 liters

Which angle of rotation is an angle of rotational symmetry for all figures?

Determine the lengths of the sides of the rectangle using the given area. give answers both exactly and approximately (to the nearest tenth). the area of the rectangle is 46 cm2.